UV Light Makes Mushrooms Rich in Vitamin D

The dog days of summer are a distant memory and so are the long bright sunny days.

But for many people, sunlight is an essential source of vitamin D. The human body needs vitamin D to maintain bone health and helps regulate the immune system.

The ultraviolet light in sunlight actually converts cholesterol in your skin into vitamin D. The vitamin is also found in foods like fatty fish and fortified cereals, milk and orange juice. But since many people do not get enough vitamin D through their diet alone, the dark winter months can leave people deficient in the vitamin.

“The exciting thing I think is how rapidly we can take a mushroom that has no vitamin D in it whatsoever, and in less than one second we can increase the vitamin D content to over 100 percent [of the recommended daily allowance],” said Michael Kalaras, a post-doctoral scholar at Penn State University in University Park, Pa.

Here’s how it works. Quick pulses of ultraviolet light flash over the mushroom’s surface, going through it, and setting off a chemical process that converts a compound similar to cholesterol inside the mushrooms into vitamin D.

“It’s already happening in a number of facilities where they’re actually doing this on conveyor belts,” said Robert Beelman, a food scientist at Penn State.

Mushrooms maintained their vitamin D levels up to a week in the refrigerator. One serving of mushrooms has a day’s worth of the recommended daily allowance of vitamin D, which is 600 IUs (or 15 micrograms) per day. Researchers suggest that smaller amounts of mushrooms may be all you need if you have other sources of vitamin D in your diet.

“We haven’t found any negative effects from our treatment,” said Kalaras.

It is possible to become sick from taking too much vitamin D, but researchers say those levels are extremely high and people are unlikely to reach them accidently.

Inside Science News Service is supported by the American Institute of Physics. Karin Heineman is the executive producer of Inside Science TV. She has produced over 600 video news segments on science, technology, engineering and math in the past 13 years for Inside Science TV and its predecessor, Discoveries and Breakthroughs Inside Science.